Credit card information was not accessed or affected, according to the company. Nor was merchants' financial or banking information.

LivingSocial suggests all customers change their passwords on their accounts. The company is in the process of emailing the customers who were affected to help them reset their passwords.

They are also working with law enforcement to investigate the breach.

"The security of our customer and merchant information is our priority," said LivingSocial CEO Tim O'Shaughnessy in the email to customers. "We always strive to ensure the security of our customer information, and we are redoubling efforts to prevent any issues in the future."

Here is the email that LivingSocial is sending to affected customers:

Subject: An important update on your LivingSocial.com account

LivingSocial recently experienced a cyber-attack on our computer systems that resulted in unauthorized access to some customer data from our servers. We are actively working with law enforcement to investigate this issue.

The information accessed includes names, email addresses, date of birth for some users, and encrypted passwords -- technically ‘hashed’ and ‘salted’ passwords. We never store passwords in plain text.

The database that stores customer credit card information was not affected or accessed.

Although your LivingSocial password would be difficult to decode, we want to take every precaution to ensure that your account is secure, so we are expiring your old password and requesting that you create a new one.

For your security, please create a new password for your <<email_address>> account by following the instructions below.
1. Visit LivingSocial.com
2. Click on the "Create a New Password" button (top right corner of the homepage)
3. Follow the steps to finish
We also encourage you, for your own personal data security, to consider changing password(s) on any other sites on which you use the same or similar password(s).

The security of your information is our priority. We always strive to ensure the security of our customer information, and we are redoubling efforts to prevent any issues in the future.

Please note that LivingSocial will never ask you directly for personal or account information in an email. We will always direct you to the LivingSocial website – and require you to login – before making any changes to your account. Please disregard any emails claiming to be from LivingSocial that request such information or direct you to a different website that asks for such information.

If you have additional questions about this process, the "Create a New Password" button on LivingSocial.com will direct you to a page that has instructions on creating a new password and answers to frequently asked questions.

We are sorry this incident occurred, and we look forward to continuing to introduce you to new and exciting things to do in your community.